Apparatus and method for processing biological material

ABSTRACT

The application discloses an apparatus and method for processing biological material, including a suspension of cells.

TECHNICAL FIELD

The present subject matter generally relates to an apparatus and method for processing biological material to concentrate and wash a biological component in the material.

BACKGROUND

Biological materials, such as cells, are used in numerous therapeutic, diagnostic and research applications. For example, stem cells may be administered to patients to obtain a desired therapeutic effect such as regeneration of tissue in vivo. In other situations, biological materials including cells may be administered for grafts, transplants, or other procedures.

To provide an effective preparation of the biological material, having sufficient concentration that may be administered to a patient or that may be useful for diagnostic and research purposes, it often is necessary to perform numerous and lengthy manipulations involving the material. For example, stem cells often are first separated and isolated from a tissue from which they are derived, such as muscle, blood or adipose (fat) tissue. The cells of such a composition then may have to be subjected to multiple rounds of purification, washing or other treatments before they can be introduced, such as by injection, into a patient. These procedures may require sequential transfer of the cells to different containers. They also may require further manipulations, such as to promote sedimentation. Each procedure preferably is performed aseptically or in a closed sterile system to limit or avoid the potential introduction of contaminating material or organisms into the composition. Alternatively, even if the cells will not be administered to a patient but, instead cultured in vitro, for example, they still may require extensive washing and concentration preferably in aseptic conditions.

Also, to be suitable for administration to a patient, it may be preferable for a preparation of biological material to be highly concentrated. This may permit a relatively small volume to be administered. For example, stem cell preparations of about 1×10⁸ cells or more generally may be concentrated into a volume of less than five (5) mls for injection into a patient.

Although much work has been done in the field of tissue processing, there continues to be a need for advances in the field of processing biological material including in the areas of washing and concentrating material for subsequent therapeutic, diagnostic, research or other applications.

SUMMARY

In one example, the subject matter of this application is directed to a sedimentation assembly for concentrating cells in a suspension. The sedimentation assembly includes a first chamber for receiving the suspension including a cell population. The first chamber has a cell concentration zone for receiving a concentrated population of the cells upon application of a sedimentation force upon the chamber. The assembly also includes a second chamber that is adapted to be removably placed in fluid communication with a fluid destination or source, including the concentration zone of the first chamber. The first and second chambers as a unit are placeable in a sedimentation force field with the first and second chambers in fluid communication for flowing a portion of the suspension including a cell population into the second chamber. The chambers are preferably physically separable so that fluid communication is effected physically by joining the chambers or broken by physically separating the chambers.

In another example, the disclosed subject matter is directed to a sedimentation assembly for washing and concentrating a cell population in a suspension. The sedimentation assembly includes a first chamber for receiving a suspension including a cell population. The sedimentation assembly also includes a second chamber, adapted to be removably placed in fluid communication with a fluid destination or source, including the first chamber. The first and second chambers are placeable as a unit in a sedimentation force field with the first and second chambers in fluid communication, such that when the unit is subjected to the sedimentation force field at least a portion of the suspension flows from the first chamber to the second chamber, thereby forming a concentrated cell suspension in the second chamber.

The disclosure also is directed to methods of concentrating cells in a suspension. In one example, a method of concentrating cells in a suspension includes collecting a suspension including a cell population within a first chamber. The cell population is sedimented to obtain a concentrated cell suspension within the first chamber and the concentrated cell suspension is flowed into a second chamber under a sedimentation force field.

In a further example, a method of concentrating and washing cells in a suspension is disclosed. The method includes collecting a suspension including a cell population within a first chamber and sedimenting the cell population to obtain a concentrated cell suspension within the first chamber. The concentrated cell suspension is flowed into a second chamber under a sedimentation force field. The second chamber is detached from the first chamber and the concentrated cell suspension is flowed into a further fluid destination or source. The further fluid destination or source is placeable together with the second chamber in a sedimentation force field.

In a further example, an apparatus for reconstituting, washing or treating a cell preparation is described. The apparatus has a first chamber with at least one port. The apparatus also includes a second chamber that has at least one port and that is adapted to be repeatedly and removably placed in fluid communication with a fluid destination or source, such as the first chamber. At least one port of the first chamber has a resealable valve and at least one port of the second chamber has a member for opening the valve.

A method for reconstituting, washing or treating a cell preparation is also disclosed. The method includes placing a cell preparation within a first chamber and flowing the cell preparation from the first chamber into a second chamber which is adapted to be repeatedly and removably connected to and placed in fluid communication with the first chamber. One of the first and second chambers has a port having an automatically resealable valve and the other of the first and second chambers has a port having a member adapted to automatically open the valve when the chambers are connected. The second chamber is then disconnected from the first chamber and the valve automatically closed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional view of one example of a sedimentation assembly according to the disclosure where first and second chambers are shown in a separated position and out of fluid communication;

FIG. 1 a is an enlarged cross-sectional view of one example of a coupling between the first and second chambers of FIG. 1, with the chambers shown in a separated position;

FIG. 2 is a partial cross-sectional view of the of sedimentation assembly of FIG. 1 with the first and second chambers shown in a connected position in fluid communication.

FIG. 2 a is an enlarged cross-sectional view of the example of a coupling between the first and second chambers of FIG. 2, with the chambers shown in a connected position;

FIGS. 3 a-3 f show one example of a method of using the sedimentation assembly of FIG. 1 according to the disclosure;

FIG. 4 is a perspective view of one example of a holder, holding a modified sedimentation assembly for use in a sedimentation force field, specifically generated by a centrifuge;

FIG. 5 shows a further example of a sedimentation assembly with a holder, such as the holder of FIG. 4;

FIG. 6 is a cross-sectional view of the example of the holder with the sedimentation assembly of FIG. 4 located in the holder;

FIGS. 7 a-7 g show an example of a method of using the sedimentation assembly of FIG. 1 according to the disclosure;

FIGS. 8 a-8 h show an example of a method of use of another sedimentation assembly according to the disclosure, where one chamber includes a plunger;

FIG. 9 is a cross-sectional view of a further example of a sedimentation assembly according to the disclosure.

FIGS. 10 a-d are cross-sectional views of further examples of valves and connectors that may be used with an apparatus disclosed herein.

DETAILED DESCRIPTION

While detailed examples are disclosed herein, it is to be understood that these disclosed examples are merely exemplary, and various aspects and features described herein may have utility alone or in combination with other features or aspects in a manner other than explicitly shown but would be apparent to a person of ordinary skill in the art.

The subject matter of the present application is directed generally to an apparatus and method for processing biological material. In one example, the apparatus is a sedimentation assembly that may be used to concentrate biological material. In other preferred examples, the sedimentation assembly may be used to reconstitute, wash and/or otherwise treat the material with desired reagents and solutions. For example, the apparatus may be used to wash or treat cell preparations with selected buffers. In other examples, the apparatus may be used to treat a cell preparation with reagents such as serum, antibodies or growth factors. In further examples, the apparatus may be used to prepare cells for freezing and storage and may be used reconstitute a cell preparation that had been frozen and which may be required to be transferred to culture media.

In other preferred examples, the apparatus may be used to reconstitute, wash or otherwise treat a preparation of cells without necessarily sedimenting the cells. For example, the apparatus may be used to transfer a thawed cell preparation to tissue culture media so that the cells may be cultured.

Turning to the accompanying drawings, FIG. 1 illustrates a sedimentation assembly generally at 10 that may be used in concentrating biological material, such as cells, from tissue. The sedimentation assembly includes a first chamber 12 that may receive biological material, such as a suspension of cells. The sedimentation assembly 10 also includes a second chamber 26 that may be placed in fluid communication with the first chamber 12, for example, as seen in FIG. 2. That is, the first chamber 12 and second chamber 26 may be readily coupled together or connected to form a sedimentation assembly 10 as a stable, integrated unit. The chambers 12, 26 then may be separated and then reconnected, if necessary, so that fluid communication between the chambers may be repeatedly established, removed and re-established. For example, FIG. 1 shows the sedimentation assembly 10 with the first and second chambers 12, 26 separated—and thus fluid communication has not yet been established or has been removed. FIG. 2 shows the assembly 10 with the two chambers connected or having been reconnected and placed in fluid communication. As shown in FIGS. 1 and 2, a coupling 32 may be used to facilitate the connection, separation and reconnection of the two chambers.

In one example, the first chamber 12 is substantially rigid and the second chamber 26 may have the same or different degree of rigidity. The chambers, for example, may be generally be more rigid than bags commonly used in blood processing procedures, but may retain a degree of flexibility. Thus, in some examples, the chambers may be sufficiently pliable such that they may be manipulated by the application of no more than an average manual force. The chambers 12, 26 may be formed, at least in part, of substantially rigid transparent plastics such that the contents may be viewed during processing. Of course, the first and second chambers need not necessarily be made of the same materials or have the same degree of rigidity. In one preferred example, at least part of the second chamber 26 may be less rigid than the first chamber 12, thereby permitting the volume of the second chamber to be manipulated or expelled by the application of force to the wall of the second chamber or by a change in pressure of the chamber.

The sedimentation assembly also is preferably disposable, and may be made from polyethylene, polypropylene or other materials that are suitable for use with biological material and that may be easily sterilized before use, or otherwise provided in a sterile form. Although typically not believed to be necessary, the chamber surfaces may be treated or coated with materials such as serum, albumin, polycations, polyanions, or other materials, as desired, using methods known in the art, to increase or decrease the adherence or affinity of selected biological material to the walls of the first and second chambers, or for other purposes.

The volumes of the first and second chambers 12, 26 may be selected depending on particular requirements. In one example, such as shown in FIG. 1, the second chamber 26 has a smaller volume than the first chamber 12. This example may be used, for example, when the suspension of cells is to be concentrated into a smaller volume for administration to a patient or for further processing. The chambers 12, 26 also may assume numerous shapes, as desired. For example, as described further herein, one or both chambers may be in the form of a syringe with a moveable plunger therein.

In the example shown in FIG. 1, the first chamber 12 has an upper wall portion 14 which is cylindrical. The upper wall portion 14 of the first chamber 12 is closed at an upper end by a wall or base 15 and is joined at a lower end to a conical or tapered portion, forming a concentration zone or area 16 within the first chamber 12, proximate its lower end. As shown in FIG. 1, an inlet tubing 20 may be attached to the first chamber 12 via an aperture 18 in the base 15. The inlet tubing 20 may be used to introduce biological material including a suspension of cells into the first chamber 12. The first chamber 12 also has an outlet 22 adjacent the lower end of the concentration zone 16. The first chamber 12 further includes a vent 24 in the base 15 to permit venting of air as may be required when fluid is being added to or removed from the first chamber 12.

In the example shown in FIGS. 1 and 2, the second chamber 26 is shown as having a substantially rigid spherical shape with a port 28 to permit the introduction and/or removal of fluid. Of course, the second chamber 26 may be constructed to be more or less flexible and to have a different shape, as desired. In this example, the second chamber 26 also includes a lower pocket or region 30 opposite the port 28. The pocket 30 provides a space or zone where cells can accumulate during sedimentation, and may facilitate later removal of a fluid from the second chamber 26 with less disruption to the cells collected in the pocket 30. Of course, the sedimented cells may be suspended within the second chamber and used directly as a final suspension for a desired purpose such as injection into a patient without further processing.

As noted above, in FIG. 1, the second chamber 26 is shown as physically separated from the first chamber 12. Therefore, the second chamber 26 has not yet established or has been removed from fluid communication with the first chamber 12. FIG. 2 shows the second chamber 26 as connected to the first chamber 12, so that the second chamber 26 is placed in fluid communication with the first chamber 12.

As shown in FIGS. 1 and 2, a separable coupling 32 may be utilized to facilitate the connection, separation and reconnection of the first chamber 12 and second chamber 26. FIGS. 1 a and 2 a show cross-sectional, enlarged views of an example coupling 32. FIG. 1 a shows an arrangement of the coupling when the chambers 12, 26 are not connected and not in fluid communication with each other. FIG. 2 a shows an arrangement when the chambers 12, 26 are connected and fluid communication between the chambers may have been established.

As shown in FIGS. 1 a and 2 a, the illustrated coupling 32 includes two mating elements. A first mating connector or element 34 of the coupling 32 is shown as being externally threaded at its upper end, and engaged with the first chamber 12 via complementary threads in the outlet 22. It will be appreciated that the first mating element 34 may be constructed in other ways to engage the first chamber 12 or may be molded with or otherwise connected to the first chamber 12. The first element 34 shown in FIGS. 1 a and 2 a also includes an outer collar 35 that is internally threaded, a blunt cannula 36, located within the collar.

A second mating connector or element 38 of the coupling 32 may be threaded, molded or otherwise connected to the second chamber 26 at its port 28. In the example illustrated in FIG. 1 a, the second mating element 38 is shown with internal threads at its lower end that engage complementary external threads extending from the port 28 at the top of the second chamber 26. The second mating element 38 also includes at its upper end an external thread or flange 37 for mating with the internally threaded collar 35 of the first mating element 34.

In this illustrated example, the second mating element 38 of the coupling 32 further includes a flexible pre-slit, re-sealable septum valve 40. As seen in FIG. 1 a, the septum valve 40 is biased towards a closed position. Therefore, the septum valve 40 automatically closes and seals the second chamber 26 from the environment when the first and second chambers 12, 26 are separated. As seen in FIG. 2 a, the septum valve 40 also automatically seals against the cannula 36 when the chambers 12, 26 are connected.

The disclosed apparatus is not limited to a particular connector or valve construction shown. For example, the above elements may be otherwise constructed or reversed in their placement, if desired. It also will be appreciated that other examples may include valves on both chambers, as desired.

To join the two chambers 12, 26 and place them in fluid communication, the first and second mating elements 34, 38 of the coupling 32 are connected together. This causes the cannula 36 to pass through the re-sealable septum valve 40, as indicated in FIG. 2 a. In this arrangement, the connector provides a closed passageway or channel 42 in the sedimentation assembly 10 that is sealed from the environment. In this regard, the septum valve is preferably elastically stretched about the penetrating member. In this example with the first and second chambers 12, 26 connected as a unit, fluid including cells i.e a cell suspension (or liquid alone), may flow in either direction (first chamber 12 to second chamber 26 or second chamber 26 to first chamber 12) depending on the direction and magnitude of forces applied to the sedimentation assembly 10. To remove the fluid communication between the chambers 12, 26, the cannula 36 is withdrawn from the septum valve 40, which automatically re-seals instantaneously.

FIGS. 3 a-3 f illustrates generally a method of use of a sedimentation assembly 10. As shown in FIGS. 3 a and 3 b, the first chamber 12, which has received a suspension of cells, may be connected to a second chamber 26 and fluid communication between the chambers may be established. A coupling 32 may be used to facilitate the connection of the two chambers, creating a sedimentation assembly 10 in the form of an integrated unit, with the chambers 12, 26 rigidly connected together by the coupling 32, as seen in FIG. 3 b.

The sedimentation assembly 10 may be placed in a sedimentation force field, such as a centrifugal force field, although a simple gravitational force field, i.e. normal gravitational force, may be sufficient to promote sedimentation in certain circumstances. The sedimentation force field, such as developed by centrifugation in FIG. 3 c, should be sufficient to cause desired cells of the suspension to become concentrated in the concentration zone 16 of the first chamber 12 and, optionally, to flow from the first chamber 12 to the second chamber 26.

After the second chamber 26 receives a quantity of the desired suspension of cells, the second chamber 26 may be separated from the first chamber 12, as illustrated in FIGS. 3 d and 3 e. Thus, the sedimentation assembly 10 may be inverted, as shown in FIG. 3 d, to reduce potential spillage as the cannula 36 is removed from the septum valve 40. The second chamber 26 then may be disconnected at the coupling 32 from the first chamber 12, such as by disengaging the internal threads of the collar 35 from the flange 37 on the second chamber 26, and withdrawing the cannula 36.

With the second chamber 26 disconnected and separated from the first chamber 12, as indicated in FIG. 3 f, the concentrated suspension of cells may be removed from the second chamber 26 such as by use of a syringe 41. If desired, the cells also may be maintained in the second chamber 26, such as for further processing. For example, the separated second chamber 26 with the desired cells may be placed in fluid communication with a further fluid destination or source, such as an additional chamber, for further treatment and concentration, as described below in reference to another example.

The example sedimentation assembly 10 may be used to reconstitute, wash, treat or concentrate a diverse set of cell preparations. For example, the biological material received by the first chamber 12 may be a relatively crude suspension of cells and may include individual cells, multi-cellular aggregates and/or cells associated with non-cellular material. The suspension of cells may include one or more cell types. The suspension of cells also may include stem cells alone or in combination with other cell types, including other types of stem cells.

The sedimentation assembly 10 also may be used with cell preparations that have been subjected to purification procedures. For example, the sedimentation assembly 10 may be linked, connected to or otherwise incorporated into a system for purifying cells. In such an arrangement, the first chamber 12 of the sedimentation assembly 10 may receive a suspension of cells from the cell purification system. For instance, the suspension of cells received by the first chamber may be stem cells that have been isolated according to the presence or absence of a selected cell marker using affinity techniques. The suspension of cells may have been, for example, isolated as being CD34 positive.

As indicated, centrifugation may be used to produce a sedimentation force field to flow a suspension of cells from the first chamber 12 to the second chamber 26. When centrifugation is used, the sedimentation assembly 10 may be placed in a holder, for convenient further placement of the assembly in a centrifuge. The holder also may assist in stabilizing the assembly during centrifugation. The size and shape of the holder may be adapted to a given sedimentation assembly and centrifuge bucket. Such a holder also may be used to hold a sedimentation assembly for sedimentation at normal gravity force.

FIGS. 4-6 show an example of a holder 44 that may be used with a further example of a sedimentation assembly 48. FIG. 4 shows the example of a holder 44 that may be used to hold a sedimentation assembly 48 in a centrifuge bucket during centrifugation. The holder includes an opening 46, best seen in FIG. 5, for placement of the sedimentation assembly into the holder 44. In this example, the overall shape of the holder generally is cylindrical, to fit the most common shape of centrifuge buckets.

FIG. 5 shows the placement of the sedimentation assembly 48 into the holder 44 of FIG. 4. As shown, the sedimentation assembly includes a first chamber 50 with a concentration zone, 52 a second chamber 54, and a coupling 56. In this example, the first chamber 50 includes an inlet 58 for receiving a suspension of cells. The inlet 58 may be covered, for example, with a screw cap 60.

In FIG. 6, the sedimentation assembly 48 is shown placed within the holder 44, shown in cross-section, for use in a sedimenting procedure, as would occur during centrifugation. During the sedimenting procedure, the desired cells, initially in the first chamber 50, will become concentrated within the concentration zone 52, and will tend to flow into the second chamber 54, via the coupling 56.

FIGS. 7 a-7 g exemplify a use of a sedimentation assembly 61 according to the disclosure for performing multiple washing and/or treating steps of a cell population. The sedimentation assembly 61 includes a first chamber 64 and a second chamber 26. In FIG. 7 a, the second chamber 26 contains a suspension of cells 62 that may require further processing. The suspension of cells in the second chamber 26 may result from processing according to previously described examples for obtaining a concentrated cell population such as is discussed, for example, with respect to use of the first chamber 12 in FIGS. 3 a-3 f.

As shown in FIG. 7 b, the second chamber 26 with the suspension of cells 62 may be placed in fluid communication with another fluid destination or source, such as an additional first chamber 64 which may contain a washing or treatment solution. The connection of the two chambers may be facilitated by the presence of a coupling, such as previously discussed coupling 32 that allows for repeated coupling (in fluid communication) and uncoupling (not in fluid communication) of the chambers. The cells 62 then may flow into the additional first chamber 64, with the flow being enhanced simply by applying manual force to a wall of the second chamber 26, such as by squeezing the second chamber 26 while the sedimentation assembly 61 is in an inverted position. It will be appreciated that a sedimentation force field, such as a centrifugal force field, also may be applied to the inverted sedimentation assembly so as to facilitate the flow of cells from the second chamber 26 to the first chamber 64.

In examples where the cells are to be washed, the suspension of cells may be flowed from the second chamber 26 to an additional first chamber 64 that contains a large volume of a wash solution. In other examples, the cells may be flowed into an additional first chamber containing a relatively small volume of fluid, as might occur when the cells are to be treated with an expensive reagent. After flowing the cells from the second chamber 26 to the additional first chamber 64, to limit cell loss the second chamber 26 may remain connected with the first chamber 64, or alternatively may be disconnected from the first chamber 64.

After washing or treatment of the cells within the additional first chamber 64, the cells may be flowed back into the second chamber 26, which remains attached to the additional first chamber thereby allowing complete recovery of all the cells or at least reducing cell loss. This may be accomplished using a sedimentation force field, such as shown in FIG. 7 c. Alternatively, the additional first chamber 64 may be connected to and placed in fluid communication with a new second chamber. The second chamber 26 then may be separated from the additional first chamber 64, resulting in a suspension of cells in the second chamber 26 that has been washed and re-concentrated, as seen in FIG. 7 d.

If desired, the washed suspension of cells in the further second chamber 26 then may be flowed to yet another first chamber 68 for further processing, such as by additional washing or treatment. The connection and flowing of the suspension of cells from the second chamber 26 to the additional first chamber 68 is represented in FIG. 7 e and is accomplished in a similar manner as with respect to the above description of FIG. 7 b. As shown in FIG. 7 f, the cells then may be flowed back to the original second chamber 26 or a new second chamber, such as by use of a sedimentation force field. The first and second chambers may remain attached and the use of the same second chamber may reduce cell loss. In this way, a suspension of cells may be repeatedly moved between “first” and “second” chambers that are placed in fluid communication, providing for repeated washing, treatment and/or re-concentration of the cells, shown deposited in the second chamber 26 in FIG. 7 g.

FIGS. 8 a-8 h shows a further example of a sedimentation assembly 70 and a method of use thereof in accordance with the disclosure. The sedimentation assembly 70 includes a first chamber 72 for receiving a cell suspension and a second chamber 76, which can be in the form of a syringe. A coupling 78 can be used to place the chambers 72, 76 in fluid communication. As described with respect to the other examples, the second chamber 76 may be placed in fluid communication with a first chamber 72. The sedimentation assembly 70 with the first chamber 72 connected to the second chamber 76 may be placed in a sedimentation force field, such as shown in FIG. 8 b, to flow a cell population 74 into the second chamber 76.

The flow of the cell population 74 to the second chamber 76, in the form of a syringe, also may be facilitated or accomplished by moving a piston 80 of the syringe 76, so as to create a vacuum in the second chamber 76, as shown by the displacement of the piston 80 in FIGS. 8 c and 8 d. This movement of the piston 80 causes fluid to be drawn into the second chamber 76 from the first chamber 72 to relieve the vacuum. The volume of the syringe chamber may be configured as fixed or variable, depending on anticipated fluid volume. In one example, retraction of the piston 80 will draw fluid into the second chamber thereby helping to recover cells that remain in the first chamber 72 or in the area of the coupling 78 even after the application of a sedimentation force field. In addition, retraction of the piston may be used to increase the amount of fluid in the second chamber, if desired. The piston 80 of the syringe 76 also may be pushed after the cell population has been flowed into the syringe 76, thereby removing excess supernatant from the second chamber and adjusting the volume in which the cells are suspended in the second chamber 76.

The second chamber 76 then may be removed from fluid communication with the first chamber 72, as illustrated in FIG. 8 e. Given that the second chamber 76 is in the form of a syringe, the second chamber 76 may be used to administer the cells to a patient or used for other purposes. As indicated in FIG. 8 f, the syringe also may be placed in fluid communication with a further fluid destination or source, such as a further first chamber 82, for further washing or treatment. The cells 74 may be flowed into the further first chamber 82 by movement of the piston 80 of the second chamber syringe 76, as shown in FIGS. 8 f and 8 g, or by application of a sedimentation force field, such as described above in reference to FIG. 8 b. The cells also may be flowed back into the second chamber 76 (or into a further “second” chamber) to result in a concentrated cell population in the second chamber 76, as shown in FIG. 8 h.

A further example of a sedimentation assembly according to the disclosure is shown in FIG. 9. According to this example, one or both chambers of the sedimentation assembly is adapted by the provision of one or more air pockets to more easily allow the trapping of air in the chamber. This feature is beneficial when it is necessary to easily compress the contents of a chamber, such as occurs, for example, when a a structure such as needle or cannula must be introduced into a chamber filled with liquid.

The sedimentation assembly 84 shown in FIG. 9 is substantially similar to the example shown in FIGS. 1 and 2. That is, the sedimentation assembly 84 includes a first chamber 86, a second chamber 88, and a coupling 90. The coupling 90 shown in FIG. 9 is identical to that shown in FIG. 1 a. In FIG. 9, the wall of the second chamber 88 curves upwards on both sides of inlet port 92, forming air-trapping pockets or regions 94 within the second chamber 88.

According to the example of FIG. 9, air is trapped in the air-trapping regions 94 when the chamber is placed upright and filled with liquid. When a syringe needle or similar device is inserted into the second chamber 88 through, for example, the septum 96, liquid is forced into the air-trapping regions because the trapped air is compressible, allowing a structure such as needle or cannula to more easily penetrate the chamber.

Further, other types of valves and couplings may be used with the sedimentation assembly of the disclosure. Resealable valves are preferred (and particularly preferably automatically resealable) to regulate the flow of fluid between the chambers, either alone or in combination with other valves. For example, stopcock valves as well as clamps are examples of manually resealable elements that may be used. In one example, a syringe-type needle may be used with a rubber plug forming a valve.

Other valves and couplings that may be used are disclosed, for example, in U.S. Pat. Nos. 4,683,916, 5,188,620, 5,957,898, 6,039,302 6,261,282 and 6,605,076 which are herein incorporated by reference in their entirety. These valves and others may employ a variety of septums and septum opening mechanisms, and may be employed with various types and shapes of coupling members such as needles, Luer members, cannulas, nozzles and hybrid structures.

FIG. 10 a-d shows examples of such valves and connectors. In FIG. 10 a, valve 100 has a resealable pre-slit septum 102 mounted on the first end 104 of a housing 106. The septum is mounted between annular, U-shaped, swaged end members 108 and an internal septum supporting ridge 110. As described more fully in U.S. Pat. Nos. 5,188,620 and 6,605,076, this septum is co-operative with a blunt cannula that may be inserted through septum slit 102 for introducing fluid into and through the valve.

A further example of a valve connector 200 is shown in FIG. 10 b. In this example, a nozzle 202 in the form of a male Luer fitting is shown partially inserted into the valve 200 to establish a fluid flow path. Briefly, the insertion of the nozzle 202 depresses a gland or elastomeric member 204 and axially displaces a hollow internal post 206 to open a fluid flow path through the gland and the hollow post to valve outlet 208.

FIG. 10 c shows a further example of a valve connector that may be used with an apparatus according to the disclosure. The valve connector 300 includes a resealable valve member 302 having an upper portion 304, middle portion 306 and annular skirt (not shown). One valve slit 308, extends downwardly through the upper portion 304 and middle portion 306 into a chamber 310. Engagement of a cannula against the face of the valve 302 causes the slit 314 to open and provides a fluid flow path through the slit and chamber 310 to the valve outlet.

FIG. 10 d shows one further valve that may be used with the present apparatus. Specifically, the valve body 400 of FIG. 10 d includes a male Luer portion 402 and a female Luer portion 404. A valve disc 406 is located within the valve body and rests on a triangular projection 408. The inherent resiliency of the valve disc normally biases it in a closed position as shown in solid lines. A valve actuator 410 is located in the female Luer bore, so that the insertion of a connecting male Luer forces the actuator 410 axially to engage and bend the edges of the valve disc 406 downwardly to an open position. The disc reseals upon removal of the connecting male Luer.

It will be understood that the examples provided in the present disclosure are illustrative of some of the applications of the principles of the present disclosure. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the disclosure. Various features which are described herein can be used in any combination and are not limited to particular combinations that are specifically described herein. 

1. A sedimentation assembly for concentrating cells in a suspension, comprising: a first chamber for receiving a suspension including a cell population, the first chamber including a cell concentration zone for receiving a concentrated population of the cells upon application of a sedimentation force upon the first chamber, said first chamber further comprising a first port in communication with said cell concentration zone; a second chamber including a second port configured to be repeatedly removably placed in fluid communication with the first port of the first chamber; and one of the first and second ports having a resealable closure and the other of the first and second ports comprising a member configured to open said resealable closure when the chambers are connected, the resealable closure being configured to automatically close when the chambers are disconnected; the first and second chambers being configured for placement together in a sedimentation force field as a unit with the first and second chambers in fluid communication, whereby upon application of the sedimentation force field said second chamber receives at least a portion of the suspension including a concentrated population of the cells from the cell concentration zone of said first chamber.
 2. The sedimentation assembly of claim 1 wherein the second chamber comprises a housing defining a substantially spherical inner chamber and wherein said second port of said second chamber has a resealable closure.
 3. The sedimentation assembly of claim 2 wherein said second chamber further comprises a cell receiving pocket generally positioned opposite said port.
 4. The sedimentation assembly of claim 1 wherein the second chamber further comprises a gas collection region.
 5. The sedimentation assembly of claim 1 wherein said second chamber is less rigid than said first chamber.
 6. The sedimentation assembly of claim 2 wherein said second chamber is compressible.
 7. The sedimentation assembly of claim 4 wherein said gas collection region is adjacent to said second port of said second chamber.
 8. The sedimentation assembly of claim 1 wherein said second chamber comprises a syringe.
 9. The sedimentation assembly of claim 1 wherein said resealable closure is selected from the group consisting of a septum, a pre-slit septum, an elastomeric member, a gland-type valve and combinations thereof.
 10. The sedimentation assembly of claim 1 wherein said member configured to open said resealable closure is selected from the group consisting of a Luer member, a needle, a cannula, a nozzle and combinations thereof.
 11. The sedimentation assembly of claim 1 wherein the first chamber has a larger volume than the second chamber.
 12. The sedimentation assembly of claim 1 wherein the first and second chambers are substantially rigid. 